Multicystic encephalopathy in abusive head trauma

Objective: The proof of abusive head trauma (AHT) in infants is difficult, especially in cases with a long posttraumatic survival period. In the acute phase, injury to the cranio-cervical junction causes disturbances in respiratory and cardiac control, leading to apnea and bradycardia. Infants who survive the acute phase may subsequently develop multicystic encephalopathy. Because some types of changes are age-dependent, examination of the patterns of brain damage in these cases could provide information about the time in which they were inflicted. In particular, this could apply to the extent of the cystic changes, namely that the severity thereof may decrease with older age upon infliction of the trauma. This could potentially date the injury and thereby help to identify the perpetrator. We present an analysis of the patterns of brain damage in cases of AHT-induced multicystic encephalopathy and comment on the possible etiology and the implications thereof. Materials: Nine archival cases of trauma-induced multicystic encephalopathy, originating between the years 2005 and 2011, were identified. In 8 of these cases, hematoxilin-eosin-stained whole-hemisphere histologic slides, as well as small histologic slides of cerebellar hemispheres, were available for the evaluation of the topographic distribution of the macroscopic and microscopic changes. Results: The cerebral hemispheres were more affected than the cerebellum. The magnitude of the cystic changes did not correlate with the age at which the trauma had occurred, nor the survival period. All cases showed asymmetrical affection of the cerebral hemispheres, which in 3 cases was very pronounced. The analysis revealed both ischemia- and hypoperfusioninduced injury patterns. Conclusion: Analysis of the magnitude and the distribution of the damage do not assist in the estimation of the period at which the trauma had occurred. The evaluation showed that ischemia, and to a lesser extent, hypoperfusion, were the major mechanisms of brain injury in these cases, which does not narrow the differential diagnosis of the underlying problem. However, in cases of multicystic encephalopathy, in the absence of a plausible medical explanation for the development of this condition, a remote (abusive) head trauma should be considered.